Sir Barnes Neville Wallis, commonly known as Barnes Wallis, (September 26, 1887 - October 30, 1979) was a British scientist, engineer and inventor. He is most well known for inventing the bouncing bomb used by the Royal Air Force on Operation Chastise to attack German dams in the Ruhr area during the Second World War. His many achievements include pioneering work on the successful R-100 airship, eclipsed by the horror of the death of its sister ship the R-101. His pre-war designed Vickers Wellington was one of the most robust airframes every developed, and pictures of its geodetic skeleton largely shot away, but still sound enough to bring its crew home safely still astonish today.

Following his achievements with the bouncing bomb, immortalized in the 1954 film The Dam Busters, Wallis subsequently designed the 'Tallboy'( 5 tonnes) and 'Grand Slam'(10 tonnes) deep penetration (or 'earthquake') bombs used to attack V1 rocket launch sites, submarine pens, other reinforced structures as well as the Tirpitz. These two devices are the fore-runners of modern bunker busting bombs, and could enter the earth at hypersonic velocity.

Wallis was knighted in 1968.

Wallis also proposed the Swing-wing but the idea was dismissed as unusable. Despite this his swing wing idea is now central to the ability to transition from low speed to supersonic flight in many modern military aircraft. His pioneering and groundbreaking BAC TSR-2 project was ignominiously scrapped in the late 60's. It was once said that he proposed using large cargo Submarines to transport oil undersea hence avoiding surface weather conditions. It is said that the story described in The Dam Busters reflected a trend through-out his lifetime, wherein his ideas were rejected by those in authority (and controlling funding sources).

Following the appalling toll in aircrew from his Dambusters project, he made a conscious effort to never endanger the lives of his test pilots, and was also a pioneer in remote control of aircraft.

Wallis appears as a character in Stephen Baxter's The Time Ships - the authorised sequel to The Time Machine. He is portrayed as a British engineer in an alternative history, where the First World War does not end in 1918, and Wallis concentrates his energies on developing a machine for time travel. As a consequence, it is the Germans who develop the bouncing bomb.